Posted by Frank N. Beans on April 12, 2011; This entry is filed under People, Safety.

In the airline world we take certain luxuries for granted. These luxuries include many safety devices: autopilots, EGPWS and TCAS to name a few. As good as these things are, they are nothing compared to the safety benefits of a good toilet.

Distraction, for a pilot, can be deadly. Some distractions can be tamed by a simple act of will but others, with a physiological component, are more difficult to bear. Take a full bladder, for example. In such a precarious state any one us will have our serenity disturbed.

Enter, therefore, the humble aircraft toilet. A simple technological solution to an age-old problem, the inflight toilet relieves the pilot, crew and passengers of stress. Be they number one or number two, these are stresses that no aviator needs.

The aircraft toilet, despite its importance, is one of the least documented devices in aviation. You will rarely see it discussed in the press (unless the subject of a new fee); it is rarely mentioned in historical documents, and you will never see it in old Hollywood movies.

While not always taken for granted — who hasn’t cursed as we await our turn, or breathed a sigh of relief when our turn arrives? — the aircraft toilet is an unheralded hero of aircraft safety. The modern vacuum toilet is a masterpiece of aviation engineering and design.

Vacuum toilets, as found on modern airliners, are a relatively recent invention. Patented in 1975 by toilet visionary James Kemper, the vacuum toilet was first installed by Boeing in 1982.

These fancy devices use a little liquid, and a vacuum sucking to clear the bowl of debris. This process is aided by a hi-tech non-stick coating on the inside of the bowl, similar to that found on your favourite frypan. The added benefit of the vacuum suck is the removal of nasty vapours.

There has been some speculation that such toilets are dangerous, with the potential for sucking out your innards if you flush while seated, but this speculation has been debunked by a comprehensive scientific study (Mythbusters etal., 2006).

While Boeing were the first major manufacturer to incorporate vacuum toilets, Airbus now also use them. It is clear that these manufacturers are aware of the important safety implications of the device; the “Bladder Evac” ECAM checklist, for example, details how to perform this vital stress-relieving function.

Before the vacuum toilet was invented airliner toilets generally used large quantities of blue liquid, circulated by electric pumps. These toilets and their liquid were heavy, maintenance intensive, and not without risk. For example, from time to time this liquid would leak out of the aircraft and freeze into a large and very unpleasant ice block on the outside of the plane. This ice block would then partially melt and break off as the aircraft descended into warmer air. The resulting blue ice stories became a favourite of the press — a giant wee-slushie smashing through a lounge room roof had all the elements of good news.

Going back further in time, before the blue liquid toilets, there is remarkably little written on the topic of “lav-tech.” We can, however, make a few assumptions…

Inflight toileting was certainly not an issue in the early days… For example, Orville Wright’s first flight lasted only 12 seconds — hardly long enough to get worked up from a bladder perspective, although one may surmise that a number two might have been on his mind.

As aviation technology progressed it was some time before the endurance of the aeroplane could outlast the endurance of the bladder. For example, in 1909 Bleriot crossed the English channel in 37 minutes, and was more concerned about getting wet from the cold seawater than from anything else. No, unless those early pioneers were old with an irritable bladder, inflight relief was not required.

Eventually, however, aircraft improved and flew longer. It is obvious that someone, somewhere, was the first person to relieve themselves in an aircraft. Who was this urinary pioneer? — history does not record. It is a reasonable presumption that bottles and tubes were involved but that information, too, is lost to time.

The years passed and aircraft continued to grow, both in endurance and passenger numbers. Other toiletry improvement were required; a bucket was installed, later improved by the addition of a lid (after a nasty experience with a full bucket and turbulence).

Shorts Empire Flying Boat, 1937

Why are there so few facts recorded about early aircraft toilets? Most likely it was the squeamishness of the age — “kill the hun but don’t mention number one.” The language of the day supported a pretense that such “unspeakables” did not exist, despite their fundamental necessity.

Air travel, in its early years, was the preserve of fabulously rich, demanding individuals who insisted on more than a slop bucket for their unmentionables. We do have documentary evidence that aircraft designers, knowing their market, started improving their toilet designs. For example, in this image of a Shorts Empire flying boat we can see fancy His and Hers toilets, complete with a Steward!

Yes, I know. None of these solutions are appealing and, perhaps, detract slightly from the glamour of flight. Tell me, then… can a full bladder ever be glamorous?

Why they don’t put toilets in little planes? A light airplane pilot may not have a fancy unspeakable for his unmentionables, but he can land in a paddock next to the nearest tree. Pretty fancy, if you ask me.